A new type of dialytic therapy - Continuous Ambulatory Peritoneal Dialysis (CAPD) - originally pioneered by NIH supported research in the United States has recently been significantly improved by Dr. Dimitrios Oreopoulos, Director of the largest peritoneal dialysis unit in the world at the Toronto Western Hospital in Canada. The specific aims of this program will be: to develop means to decrease the high incidence of peritonitis associated with this mode of therapy; to define a mode of therapy acceptable from the medical (blood chemistry, patient outcome) as well as the patient (social) point of view; to study the long term effects of this mode of therapy; and to study the endogenous defense mechanisms (macrophages) that are responsible for the protection of the patient against peritonitis.